Question

me ajudem amoress ! pfvrrrr

Answer 1

Irei resolver pelo método da soma.

a)
{x+y=20
{x-y=6. +
-------------
2X=26
X=26/2
X=13

X+Y=20
13+Y=20
Y=20-13
Y=7

S: X=13 e Y=7

b)
{x+y=2 .(-1)
{x+2y=7

{-x-y=-2
{x+2y=7. +
--------------
y=5

x+2y=7
x+2.5=7
x+10=7
x=7-10
x=-3

S: X= -3 e Y=5

c)
{2x+y=6 .(-1)
{2x+3y=2


{-2x-y=-6
{2x+3y=2. +
------------------
2y=8
y=8/2
y=4

2x+3y=2
2x+3.4=2
2x+12=2
2x=2-12
2x=10
x=10/2
x=5

S: X=5 e Y=4